function s1_generate_a_series_of_files(){
	for i in {1..100};
	do
		echo $i > /tmp/new_file$i;
	done
}
function s2_list_4_files_in_long_format_about_account_and_group(){
ls -| /etc/
{passwd,shadow,group,gshadoww} | sort 
}
function s3_find_items_related_to_given_username(){
	grep -h $1 /etc/{passwd,shadow} | sort
}
function s4_find_items_related_to_given_group_name(){
	grep -h $1 /etc/{group,gshadow} | sort
}
function s5_create_groups_for_given_group_names(){
	groupadd rnd
	groupadd itoperation
}
function s6_create_users_and_set_their_group_as_required(){
useradd adam
useradd bob
useradd calvin
useradd david
useradd edward
usermod -a -G rnd adam
usermod -a -G rnd bob
usermod -a -G rnd edward
usermod -a -G itoperation calvin
usermod -a -G itoperation david
}
function s7_change_users_shell(){
	usermod -s /usr/bin/sh adam
	usermod -s /usr/bin/sh edward
}
function s8_set_password_change_policy(){
	passwd -n 10 -x 60 -w 10 adam
	passwd -n 10 -x 60 -w 10 bob
	passwd -n 10 -x 60 -w 10 david
	passwd -n 10 -x 60 -w 10 calvin
	passwd -n 10 -x 60 -w 10 edward
}
function s9_set_password_for_five_users(){
usernames=(adam bob calvin david edward)
password=("$1" "$2" "$3" "$4" "$5")
for((i=0;i<5;i++));
do
echo "${username[$i]}:${passwords[$i]}" |chpasswd
done
}
function s10_lock_bobs_password(){
	usermod -L bob
}
function s11_include_adam_into_wheel_group(){
usermod -aG wheel adam
}
function s12_change_files_permission(){
for((i=1;i<=100;i++));
do
   filename="/tmp/new_file${i}"
   echo -n "$i" > $filename
   if(($i%3==0));
   then
        chmod 640 $filename
   fi
   done
}         
